GNAS1 T393C polymorphism is associated with clinical course in patients with intrahepatic cholangiocarcinoma

The Role of Single-Nucleotide Polymorphisms in Cholangiocarcinoma: A Systematic Review

Single-nucleotide polymorphisms (SNPs) play an essential role in various malignancies, but their role in cholangiocarcinoma (CCA) remains to be elucidated. Therefore, the purpose of this systematic review was to evaluate the association between SNPs and CCA, focusing on tumorigenesis and prognosis. A systematic literature search was carried out using PubMed, Embase, Web of Science and the Cochrane database for the association between SNPs and CCA, including literature published between January 2000 and April 2022. This systematic review compiles 43 SNPs in 32 genes associated with CCA risk, metastatic progression and overall prognosis based on 34 studies. Susceptibility to CCA was associated with SNPs in genes related to inflammation (PTGS2/COX2, IL6, IFNG/IFN-γ, TNF/TNF-α), DNA repair (ERCC1, MTHFR, MUTYH, XRCC1, OGG1), detoxification (NAT1, NAT2 and ABCC2), enzymes (SERPINA1, GSTO1, APOBEC3A, APOBEC3B), RNA (HOTAIR) and membrane-based proteins (EGFR, GAB1, KLRK1/NKG2D). Overall oncological prognosis was also related to SNPs in eight genes (GNB3, NFE2L2/NRF2, GALNT14, EGFR, XRCC1, EZH2, GNAS, CXCR1). Our findings indicate that multiple SNPs play different roles at various stages of CCA and might serve as biomarkers guiding treatment and allowing oncological risk assessment. Considering the differences in SNP detection methods, patient ethnicity and corresponding environmental factors, more large-scale multicentric investigations are needed to fully determine the potential of SNP analysis for CCA susceptibility prediction and prognostication.

CC Genotype of GNAS c.393C>T (rs7121) Polymorphism Has a Protective Effect against Development of BK Viremia and BKV-Associated Nephropathy after Renal Transplant

The GNAS gene encodes the alpha-subunit of the stimulatory G-protein (Gαs) in humans and mice. The single-nucleotide polymorphism of GNAS, c.393C>T, is associated with an elevated production of Gαs and an increased formation of cyclic adenosine monophosphate (cAMP). In the present study, we analyzed the effect of this GNAS polymorphism on a renal allograft outcome. We screened a cohort of 436 renal allograft recipients, who were retrospectively followed up for up to 5 years after transplant. GNAS genotypes were determined with polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assays. The 393T allele was detected in 319 (73%) recipients (113 recipients with TT and 206 with CT genotype) and the CC genotype in 117 (27%). The CC genotype was associated with a significantly lower frequency of BK viremia (CC, 17 recipients (15%); T 84 (26%)); p = 0.01; TT, 27 vs. CC, 17, p = 0.07; TT, 27 vs. CT, 57, p = 0. 46; CT, 57 vs. CC, 17, p = 0.01) and BKV-associated nephropathy (CC, 3 recipients (3%); T, 27 (8%); p = 0.03; TT,10 vs. CC, 3, p = 0.04; TT, 10 vs. CT,17, p = 0.85; CT, 17 vs. CC,3, p = 0.04) after transplant. BKV-associated nephropathy-free survival was significantly better among CC genotype carriers than among T allele carriers (p = 0.043; TT vs. CC, p = 0.03; CT vs. CC, p = 0.04; TT vs. CT, p = 0.83). Multivariate analysis indicated an independent protective effect of the CC genotype against the development of both BK viremia (relative risk. 0.54; p = 0.04) and BKV-associated nephropathy after renal transplant (relative risk. 0.27; p = 0.036). The GNAS 393 CC genotype seems to protect renal allograft recipients against the development of BK viremia and BKV-associated nephropathy.

The GNAS SNP c.393C>T (rs7121) as a marker for disease progression and survival in cancer

G-protein receptor signaling plays a key role in multiple signal transduction pathways. Aberrant activity of the stimulatory G_sα subunit has been frequently associated with cancer. GNAS sequence alterations and conformational changes of G_sα can both enhance or diminish its function and change downstream effects of G-protein receptor signaling. In this review and meta-analysis, we focus on the synonymous SNP rs7121 (FokI, c.393C>T), which is associated with either tumor progression or prolonged survival in cancer patients (overall hazard ratio = 2.256; p < 0.001). We finally point out the relevance of GNAS rs7121 as a promising biomarker and a prediction tool for therapy response and the need of further experiments to implement it into routine clinical diagnostics.

Elevated expression of Gsα in intrahepatic cholangiocarcinoma associates with poor prognosis

BACKGROUND

The stimulatory G protein a subunit (G_sα) plays important roles in diverse cell processes including tumorigenesis. Activating mutations in G_sα gene (GNAS) have been reported to be associated with poor prognosis in various human carcinomas. Furthermore, G_sα signaling is crucial in promoting liver regeneration by interacting with growth factor signaling, indicating that G_sα might play a promoting role in cancer development. However, little is known about the correlation between G_sα levels and clinicopathological parameters in intrahepatic cholangiocarcinoma (ICC).

METHODS

We performed immunoblotting to examine the expression levels of G_sα and Ki67 proteins in tumor tissues and the corresponding adjacent tissues. A total of 74 pair of specimens resected from 74 ICC patients were examined. The association between G_sα levels and clinicopathological findings and prognosis of the patients was evaluated.

RESULTS

Western blotting demonstrated that the expression of G_sα was significantly higher in ICC tissues compared with that in their corresponding adjacent tissues. G_sα protein was highly expressed in about half of ICC tissues (48.6%, 36/74) while only 28.4% (21/74) of tumor adjacent tissues showed G_sα high expression (P=0.011). High G_sα expression in ICC was significantly associated with the numbers of tumor nodules (P=0.037) and lymph node metastases (P=0.010). Moreover, the level of G_sα was significantly and positively correlated with Ki67 expression (P<0.001). In addition, the recurrence-free survival rate and overall survival rate in the G_sα high group were significantly lower than those in the G_sα low group (P=0.004 and P=0.005, respectively).

CONCLUSIONS

High G_sα expression is correlated with poor prognosis in ICC patients. G_sα might serve as a potential prognostic indicator of ICC.

Analysis of the influence of the T393C polymorphism of the GNAS gene on the clinical expression of primary hyperparathyroidism

BACKGROUND

The receptor of parathyroid hormone and parathyroid hormone-related-protein (PTH/PTHrp) is located in the cell membrane of target tissues - kidney and osteoblasts. It is a G protein-coupled-receptor whose G_sα subunit is encoded by the GNAS gene. Our aim was to study whether the single nucleotide polymorphism (SNP) T393C of the GNAS gene is associated with renal stones, bone mineral density (BMD), or bone remodelling markers in primary hyperparathyroidism (PHPT).

METHODS

An analysis was made of clinical and biochemical parameters and densitometric values in three areas and their relationship with the T393C SNP of the GNAS gene in 261 patients with primary hyperparathyroidism and in 328 healthy controls. Genotyping was performed using the Custom Taqman^® SNP Genotyping assay.

RESULTS

The genotype frequencies of GNAS T/C 393 were similar in the control and PHPT groups. No association was found between genotypes and clinical expression of PHPT (renal stones and bone fractures). A nonstatistically significant trend was seen to lower BMD in the lumbar spine, femoral neck, and total hip in both PHPT and control C homozygote subjects.

CONCLUSION

Genetic susceptibility to PHPT related to the GNAS T393C polymorphism or a major influence in its development and clinical expression were found. A C allele-related susceptibility to lower BMD in trabecular bone in both PHPT and control subjects is not sufficient to suggest a more severe clinical expression of PHPT. This trend may be considered as a basis for further studies with larger sample sizes and complementary functional evaluation.

Loss of Gsα impairs liver regeneration through a defect in the crosstalk between cAMP and growth factor signaling

BACKGROUND & AIMS

The stimulatory G protein α subunit (Gsα) activates the cAMP-dependent pathway by stimulating the production of cAMP and participates in diverse cell processes. Aberrant expression of Gsα results in various pathophysiological disorders, including tumorigenesis, but little is known about its role in liver regeneration.

METHODS

We generated a hepatocyte-specific Gsα gene knockout mouse to demonstrate the essential role of Gsα in liver regeneration using a mouse model with 70% partial hepatectomy (PH) or an intraperitoneal injection of carbon tetrachloride (CCl4).

RESULTS

Gsα inactivation dramatically impaired liver regeneration and blocked proliferating hepatocytes in G1/S transition due to the simultaneous depression of cyclin-dependent kinase 2 (CDK2) and cyclin E1. Loss of Gsα led to a fundamental alteration in gene profiles. Among the altered signaling cascades, the MAPK/Erk pathway, which is downstream of growth factor signaling, was disrupted secondary to a defect in phosphorylated Raf1 (pRaf1), resulting in a deficiency in phosphorylated CREB (pCREB) and CDK2 ablation. The lack of pRaf1 also resulted in a failure to phosphorylate retinoblastoma, which releases and activates E2F1, and a decrease in cyclin E1. Although these factors could be phosphorylated through both Gsα and growth factor signaling, the unique function of Raf1 in the growth factor cascade collapsed in response to the lack of Gsα.

CONCLUSION

The growth factor signaling pathway that promotes hepatocyte proliferation is dependent on Gsα signaling. Loss of Gsα leads to a breakdown of the crosstalk between cAMP and growth factor signaling and dramatically impairs liver regeneration.

Co‑expression of the carbamoyl‑phosphate synthase 1 gene and its long non‑coding RNA correlates with poor prognosis of patients with intrahepatic cholangiocarcinoma

The mechanisms leading to high rates of malignancy and recurrence of human intrahepatic cholangiocarcinoma (ICC) remain unclear. It is difficult to diagnose and assess the prognosis of patients with ICC in the clinic due to the lack of specific biomarkers. In addition, long non-coding RNAs (lncRNAs) have been reported to serve important roles in certain types of tumorigenesis however a role in ICC remains to be reported. The aim of the current study was to screen for genes and lncRNAs that are abnormally expressed in ICC and to investigate their biological and clinicopathological significance in ICC. The global gene and lncRNA expression profiles in ICC were measured using bioinformatics analysis. Carbamoyl-phosphate synthase 1 (CPS1) and its lncRNA CPS1 intronic transcript 1 (CPS1-IT1) were observed to be upregulated in ICC. The expression of CPS1 and CPS1-IT1 was measured in 31 tissue samples from patients with ICC and a number of cell lines. The effects of CPS1 and CPS1-IT1 on the proliferation and apoptosis of the ICC-9810 cell line were measured. In addition, the clinicopathological features and survival rates of patients with ICC with respect to the gene and lncRNA expression status were analyzed. CPS1 and CPS1-IT1 were co-upregulated in ICC tissues compared with non-cancerous tissues. Knockdown of CPS1 andor CPS1-IT1 reduced the proliferation and increased the apoptosis of ICC-9810 cells. Additionally, clinical analysis indicated that CPS1 and CPS1-IT1 were associated with poor liver function and reduced survival rates when the relative expression values were greater than 4 in cancer tissues. The comparisons between the high CPS1 expression group and the low expression group indicated significant differences in international normalized ratio (P=0.048), total protein (P=0.049), indirect bilirubin (P=0.025), alkaline phosphatase (P=0.003) and disease-free survival (P=0.034). In addition, there were differential trends in CA19-9 (P=0.068), globulin (P=0.052) and total bilirubin (P=0.066). The comparisons between the high CPS1-IT1 expression group and the low expression group indicated significant differences in lymphatic invasion (P=0.045), carbohydrate antigen 19-9 (P=0.044), disease-free survival (P=0.026), and non-significant differential trends in alkaline phosphatase were observed (P=0.085). In conclusion, CPS1 and CPS1-IT1 may serve an important role in ICC development by promoting the proliferation of ICC cells. Furthermore, CPS1 and CPS1-IT1 were associated with poor liver function and reduced survival rates. Thus, CPS1 and CPS1-IT1 may be potential prognostic indicators for patients with ICC.

TT genotype of GNAS1 T393C polymorphism predicts better outcome of advanced non-small cell lung cancer patients

AIM: To evaluate the potential prognostic value of GNAS1 T393C polymorphism in advanced non-small cell lung cancer.

METHODS: We extracted genomic DNA from the peripheral blood leucocytes of 94 patients with advanced non-small cell lung cancer. Quantitative real-time polymerase chain reaction was used to determine the allelic discrimination. The correlation between genotype and overall survival was evaluated using the multivariate analysis and Kaplan-Meier approach.

RESULTS: Thirty-eight out of 94 (40%) patients displayed a TT genotype, 29 out of 94 (31%) a CT genotype and 27 out of 94 (29%) a CC genotype. The median survival of TT (25 mo) genotype carriers was longer than CT (12 mo) or CC (8 mo) genotype carriers. The favorable TT genotype predicted better overall survival (OS) (2-year OS: 48%; P =0.01) compared with CT (2-year OS: 18%) or CC (2-year OS: 15%) genotype. However, dichotomization between C-genotypes (CC + CT) and T-genotypes (TT) revealed significantly lower survival rates (2-year OS: 16%; P = 0.01) for C allele carriers.

CONCLUSION: Our data provided strong evidence that the GNAS1 T393C genetic polymorphism influenced the prognosis in advanced non-small lung cancer with a worse outcome for C allele carriers.

Homozygous GNAS 393C-allele carriers with locally advanced esophageal cancer fail to benefit from platinum-based preoperative chemoradiotherapy

BACKGROUND

Currently, patients with locally advanced esophageal cancer receive neoadjuvant chemoradiotherapy but only about half of these patients benefit from this treatment. GNAS T393C has been shown to predict the postoperative course in solid tumors and may therefore be useful for treatment stratification. The aim of the present study was to determine if the single-nucleotide polymorphism GNAS T393C can be used for treatment stratification in esophageal cancer patients.

METHODS

A total of 596 patients underwent surgical resection for esophageal carcinoma from 1996 to 2008; 279 patients received chemoradiotherapy prior to surgery (RTX-SURG group). All patients and a reference group of 820 healthy White individuals were genotyped for GNAS T393C.

RESULTS

The 5-year-survival rate for the 317 patients who underwent esophagectomy as initial treatment (SURG group) was 57 % for homozygous C-allele carriers (n = 99) and 43 % for T-allele carriers (n = 218; log- rank test p = 0.025). Multivariate analysis revealed the GNAS T393C genotype (p = 0.034), pT (p < 0.001), pN (p < 0.001) and age (p < 0.001) as prognostic of survival. Homozygous C-allele carriers with a locally advanced tumor stage (cT3/T4, n = 129) in the SURG group had a 5-year survival rate of 37 %, which, remarkably, exceeded the 5-year survival rate of 30 % for the entire RTX-SURG group (n = 279). In the RTX-SURG group, the GNAS T393C genotype did not show any prognostic significance.

CONCLUSIONS

Patients with a locally advanced esophageal cancer and an homozygous GNAS 393C genotype do not benefit from platinum-based neoadjuvant chemoradiotherapy, indicating that these patients should be treated by alternative treatment strategies.

Gαs protein expression is an independent predictor of recurrence in prostate cancer

Background. T393C polymorphism in the gene GNAS1, which encodes the G-protein alpha s subunit (Gαs) of heterotrimeric G protein, is significantly associated with the clinical outcome of patients suffering from several cancers. However, studies on the role and protein expression of Gαs subunit in prostate cancer were still unavailable. Methods. The immunohistochemical staining was used to assess Gαs expression through tissue microarray procedure of 56 metastatic PCas, 291 localized PCas, and 67 benign hyperplasia (BPH). Gαs expression was semiquantitatively scored and evaluated the correlation with pathologic parameters and biochemical recurrence of prostate-specific antigen (PSA). Results. Gαs expression was localized in nuclear and cytoplasm in prostate cancer cells and downregulated in metastatic PCa compared to localized PCa and BPH (P < 0.001). Gαs was inversely associated with PSA level and Gleason scores; patients with low expression of Gαs had adverse clincopathological features. In multivariable Cox regression analysis, high Gαs expression and Gleason scores were independent predictors of both PSA progression-free and overall survival. Conclusions. Gαs down-expression is associated with adverse pathologic features and clinical PSA biochemical recurrence of prostate cancer. Gαs is an independent predictor to help determine the risk of PSA progression and death.

Evidence for genetic linkage between a polymorphism in the GNAS gene and malaria in South Indian population

The complex imprinted GNAS locus which encodes G-alpha subunit (Gαs) is involved in a number of G-protein coupled signaling pathways in eukaryotic cells. Erythrocyte invasion by Plasmodium falciparum parasites is significantly regulated by protein of GNAS gene. This study was designed to evaluate the association between single nucleotide polymorphisms (SNPs) present in GNAS locus and susceptibility to malaria. In this case control study, individuals affected by P. falciparum malaria (n=230), Plasmodium vivax malaria (n=230) and normal controls (n=230) were tested for the association of eighteen (18) known SNPs to evaluate their role in the onset of the disease. There was no significant difference in genotype frequencies of all the SNPs tested between P. falciparum and P. vivax affected individuals. However, when Bonferroni correction for multiple comparisons were performed as a control, our results demonstrated alleles and genotypes of rs7121: C>T (NC_000020.10:g.57478807C>T), a silent polymorphism situated in the exon 5, were significantly (p<0.05) associated with susceptibility to malaria in the South Indians participants. Our results demonstrate that population specific polymorphisms that exist in GNAS gene may alter the risk of occurrence of malaria.

The T393C polymorphism of GNAS1 is a predictor for relapse and survival in resectable non-small cell lung cancer

INTRODUCTION

The GNAS1 T393C single nucleotide polymorphism (T393C-SNP) correlates with Gαs mRNA stability and protein expression and augmented apoptosis. Genetic germ line variations as stable and reproducible markers potentially serve as prognostic marker in oncology. The aim of this study was to evaluate the potential prognostic value of T393C-SNP in complete resected non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

In total 163 Caucasian patients, who had been surgically treated for NSCLC between 1998 and 2010, were included in this study. Genotyping of peripheral blood cells was performed by polymerase chain reaction and digestion using the restriction enzyme FokI. The T393C-SNP was correlated with clinic-pathological parameters and survival. Chi-square test, Kaplan-Meier estimator and cox regression hazard model were used to assess the prognostic value of the T393C-SNP.

RESULTS

C-allele carriers had a higher recurrence rate (p=0.018) and a shorter disease-free survival compared to homozygous T-allele carriers (12.26 months vs. 44.65 months, p=0.009). The overall survival in homozygous C allele carriers was shorter (19.10 months vs. 53.95 months, p=0.019). Multivariate Cox regression identified the CC genotype as a negative independent prognostic factor for recurrence (hazard ratio 2.36, p=0.007) and survival (hazard ratio 2.51, p=0.008).

CONCLUSION

Determination of T393C-SNP preoperatively potentially allows allocation of NSCLC patients into different risk profiles and may influence the therapeutic strategy.

The T393C polymorphism of GNAS1 as a predictor for chemotherapy sensitivity and survival in advanced non-small-cell lung cancer patients treated with gemcitabine plus platinum

PURPOSE

The GNAS1 gene is linked to proapoptotic signaling and correlates closely with clinical outcomes in many human cancers. The aim of this study was to evaluate whether the T393C polymorphism of the GNAS1 gene could be used as a chemotherapy sensitivity and prognosis predictive marker of advanced non-small-cell lung cancer (NSCLC) treated with gemcitabine plus platinum (GP).

METHODS

In this study, we performed the PCR-restriction fragment length polymorphism assay to examine the genotypes of the GNAS1 T393C polymorphism in 131 peripheral blood DNA specimens from advanced NSCLC patients with GP treatment.

RESULTS

The frequencies of the CC, CT, and TT genotypes in 131 advanced NSCLC cases were 25.2, 47.4, and 26.7%, respectively. The favorable TT genotype was significantly correlated with better overall survival (OS; P < 0.05) and longer progress-free survival (PFS; P < 0.05) compared with the CT or CC genotype. In the multivariate Cox proportional hazards model, the GNAS1 T393C polymorphism was independently associated with overall survival after adjusting the clinicopathological factors (P < 0.05).

CONCLUSIONS

This study suggests that the TT genotype of the GNAS1 T393C polymorphism could be an independent prognostic marker to predict chemotherapy sensitivity, favorable OS and PFS in advanced NSCLC patients with GP treatment.

Extra-long Gαs variant XLαs protein escapes activation-induced subcellular redistribution and is able to provide sustained signaling

Murine models indicate that Gαs and its extra-long variant XLαs, both of which are derived from GNAS, markedly differ regarding their cellular actions, but these differences are unknown. Here we investigated activation-induced trafficking of Gαs and XLαs, using immunofluorescence microscopy, cell fractionation, and total internal reflection fluorescence microscopy. In transfected cells, XLαs remained localized to the plasma membrane, whereas Gαs redistributed to the cytosol after activation by GTPase-inhibiting mutations, cholera toxin treatment, or G protein-coupled receptor agonists (isoproterenol or parathyroid hormone (PTH)(1-34)). Cholera toxin treatment or agonist (isoproterenol or pituitary adenylate cyclase activating peptide-27) stimulation of PC12 cells expressing Gαs and XLαs endogenously led to an increased abundance of Gαs, but not XLαs, in the soluble fraction. Mutational analyses revealed two conserved cysteines and the highly charged domain as being critically involved in the plasma membrane anchoring of XLαs. The cAMP response induced by M-PTH(1-14), a parathyroid hormone analog, terminated quickly in HEK293 cells stably expressing the type 1 PTH/PTH-related peptide receptor, whereas the response remained maximal for at least 6 min in cells that co-expressed the PTH receptor and XLαs. Although isoproterenol-induced cAMP response was not prolonged by XLαs expression, a GTPase-deficient XLαs mutant found in certain tumors and patients with fibrous dysplasia of bone and McCune-Albright syndrome generated more basal cAMP accumulation in HEK293 cells and caused more severe impairment of osteoblastic differentiation of MC3T3-E1 cells than the cognate Gαs mutant (gsp oncogene). Thus, activated XLαs and Gαs traffic differently, and this may form the basis for the differences in their cellular actions.

SNPs in genes encoding G proteins in pharmacogenetics

Heterotrimeric guanine-binding proteins (G proteins) transmit signals from the cell surface to intracellular signal cascades and are involved in various physiological and pathophysiological processes. Polymorphisms in the genes GNB3 (encoding the Gβ3 subunit), GNAS (encoding the Gαs subunit) and GNAQ (encoding the Gαq subunit) have been the primary focus of investigation. Polymorphisms in these genes could be associated with different complex phenotypes underlining that alterations in G-protein signaling can cause multiple disorders. G proteins present a point of convergence or ‘bottleneck’ between various receptors and effectors, thus making them a sensible tool for pharmacogenetic studies. The pharmacogenetic studies performed to date mostly demonstrate an association between G-protein polymorphisms and response to therapy or occurrence of adverse drug effects. Therefore, polymorphisms in genes encoding G-protein subunits may help to individualize drug treatment in various diseases with regard to both efficacy and safety.

The GNAS1 T393C single nucleotide polymorphism predicts the natural postoperative course of complete resected esophageal cancer

BACKGROUND

Genetic variations in cancer patients may serve as important prognostic indicators of clinical outcome. The GNAS1 T393C single nucleotide polymorphism (SNP) diversely correlates with the clinical outcome in cancer. The aim of this study was to evaluate the potential prognostic value of T393C-SNP in complete resected only surgically treated esophageal cancer (EC).

METHODS

Genomic DNA was extracted from peripheral blood leucocytes of 190 patients who underwent only complete surgical resection for EC. T393C-SNP was correlated with clinic-pathological parameters, tumor cell dissemination in bone marrow (DTC) and clinical outcome.

RESULTS

T-allele carriers had more advanced disease due to presence of lymph node metastasis (P < 0.0001) and DTC (P = 0.01) and higher recurrence rate (P = 0.01) compared to CC genotype. The disease-free (P < 0.001) and overall survival (P < 0.001) was better in CC compared to TT and TC patients. In the multivariate Cox regression disease-stage adjusted analysis the T393C-SNP was identified as a strong independent prognostic factor for recurrence (hazard ratio 1.8, P = 0.01) and survival (hazard ratio 2.5, P < 0.001) in EC patients.

CONCLUSION

Determination of T393C-SNP preoperatively will allow allocation of EC patients into different risk profiles which may help to stratify patients eligible for neoadjuvant and or adjuvant therapy.

Prognostic assessment of three single-nucleotide polymorphisms (GNB3 825C>T, BCL2-938C>A, MCL1-386C>G) in extrahepatic cholangiocarcinoma

BACKGROUND/AIMS

Cholangiocellular carcinoma (CCA) has a devastating prognosis and markers enabling a precise prediction of the clinical outcome have long remained scarce. Recently, it has been demonstrated that genotype distribution of several single-nucleotide polymorphisms (SNPs) in genes that modulate G protein-signal transduction and apoptosis can serve as helpful predictive parameters in various carcinomas. We here aimed at extending the panel of SNPs suitable for predicting the outcome of CCA.

METHODOLOGY

Forty Caucasian patients with extrahepatic CCA and 40 age- and sex-matched healthy white Caucasians were genotyped to elucidate putative associations between clinical outcome and genotypes of the three following SNPs: G protein beta 3 (GNB3) 825C>T, B-cell-lymphoma-2 (Bcl-2) -938C>A, and myeloid cell leukemia-1 (Mcl-1) -386C>G.

RESULTS

Patients homozygous for the C allele of the GNB3 825C>T polymorphism exhibited a significant prolonged overall survival compared with patients displaying the CT or TT genotype (median survival [months]: 31 vs. 13 vs. 7; p < .05) and also showed lower bilirubin serum levels. Additionally, the CC genotype of the BCL2-938C>A polymorphism was associated with higher GLDH serum activities (U/l; 29.8 +/- 7.1 vs. 11.4 +/- 4.3 vs. 5.6 +/- 1.7 comparing CC vs. CA vs. AA; p < .05). Genotype distributions for all SNPs were not significantly different in patients vs. controls.

CONCLUSIONS

GNB3 825C>T SNP may be a novel independent prognostic marker for patients suffering from extrahepatic CCA with the CC genotype to be associated with a favorable clinical outcome. Further prospective studies are needed to confirm these results and reveal additional functional SNP effects.

The War on Cancer rages on

In 1971, the "War on Cancer" was launched by the US government to cure cancer by the 200-year anniversary of the founding of the United States of America, 1976. This article briefly looks back at the progress that has been made in cancer research and compares progress made in other areas of human affliction. While progress has indeed been made, the battle continues to rage on.

Association of the GNAS1 T393C polymorphism with tumor stage and survival in gastric cancer

AIM: To analyze the impact of the GNAS1 T393C polymorphism on prognosis and histopathology of gastric cancer.

METHODS: Genomic DNA was extracted from paraffin-embedded tissues of 122 patients with primary gastric carcinoma and from the blood of 820 healthy white individuals. Allelic discrimination was performed by quantitative real-time polymerase chain reaction. Genotyping was correlated with histopathologic parameters and with overall survival according to the Kaplan-Meier approach and with multivariate analysis by multiple stepwise regression.

RESULTS: Thirty-nine (32%) patients displayed a CC genotype, 57 (46.7%) a CT genotype and 26 (21.3%) a TT genotype. The frequency of the C allele (fC) in the patient group was 0.55, which was not significantly different from that of healthy blood donors. The distribution was compatible with the Hardy-Weinberg equilibrium. Analysis of clinicopathological parameters did not show any significant correlation of the T393C genotype with gender (P = 0.50), differentiation (P = 0.29), pT-category (P = 0.19), pN-category (P = 0.30), pM-category (P = 0.25), R-category (P = 0.95), the classifications according to WHO (P = 0.34), Laurén (P = 0.16), Goseki (P = 1.00) and Ming (P = 0.74). Dichotomization between C+ (CC+CT) and C-genotypes (TT), however, revealed significantly more advanced tumor stages (P = 0.023) and lower survival rates (P = 0.043) for C allele carriers.

CONCLUSION: The present study provides strong evidence to suggest that the GNAS1 T393C allele carrier status influences tumor progression and survival in gastric cancer with higher tumor stages and a worse outcome for C allele carriers.

Heterotrimeric G proteins and apoptosis: intersecting signaling pathways leading to context dependent phenotypes

Apoptosis, a programmed cell death mechanism, is a fundamental process during the normal development and somatic maintenance of all multicellular organisms and thus is highly conserved and tightly regulated through numerous signaling pathways. Apoptosis is of particular clinical importance as its dysregulation contributes significantly to numerous human diseases, primarily through changes in the expression and activation of key apoptotic regulators. Each of the four families of heterotrimeric G proteins (G(s), G(i/o), G(q/11) and G(12/13)) has been implicated in numerous cellular signaling processes, including proliferation, transformation, migration, differentiation, and apoptosis. Heterotrimeric G protein signaling is an important but not widely studied mechanism regulating apoptosis. G protein Signaling and Apoptosis broadly cover two large bodies of literature and share numerous signaling pathways. Examination of the intersection between these two areas is the focus of this review. Several studies have implicated signaling through each of the four heterotrimeric G protein families to regulate apoptosis within numerous disease contexts, but the mechanism(s) are not well defined. Each G protein family has been shown to stimulate and/or inhibit apoptosis in a context-dependent fashion through regulating numerous downstream effectors including the Bcl-2 family, NF-kappaB, PI3 Kinase, MAP Kinases, and small GTPases. These cell-type specific and G protein coupled receptor dependent effects have led to a complex body of literature of G protein regulation of apoptosis. Here, we review the literature and summarize apoptotic signaling through each of the four heterotrimeric G protein families (and the relevant G protein coupled receptors), and discuss limitations and future directions for research on regulating apoptosis through G protein coupled mechanisms. Continued investigation in this field is essential for the identification of important targets for pharmacological intervention in numerous diseases.

Neoplasia: the second decade

This issue marks the end of the 10-year anniversary of Neoplasia where we have seen exciting growth in both number of submitted and published articles in Neoplasia. Neoplasia was first published in 1999. During the past 10 years, Neoplasia has dynamically adapted to the needs of the cancer research community as technologies have advanced. Neoplasia is currently providing access to articles through PubMed Central to continue to facilitate rapid broad-based dissemination of published findings to the scientific community through an Open Access model. This has in part helped Neoplasia to achieve an improved impact factor this past year, demonstrating that the manuscripts published by Neoplasia are of great interest to the overall cancer research community. This past year, Neoplasia received a record number of articles for review and has had a 21% increase in the number of published articles.

GNAS1 T393C polymorphism is associated with histopathological response to neoadjuvant radiochemotherapy in esophageal cancer

Recent studies have shown an association between the GNAS1 T393C polymorphism and clinical outcome for various solid tumors. In this study, we genotyped 51 patients from an observational trial on cisplatin/5-FU-based neoadjuvant radiochemotherapy of locally advanced esophageal cancer (cT2-4, Nx, M0) and genotyping was correlated with histomorphological tumor regression. The C-allele frequency in esophageal cancer patients was 0.49. Pearson's chi(2)-test showed a significant (P<0.05) association between tumor regression grades and T393C genotypes. Overall, 63% of the patients in the T-allele group (TT+CT) were minor responders with more than 10% residual vital tumor cells in resection specimens, whereas T(-) genotypes (CC) showed a major histopathological response with less than 10% residual vital tumor cells in 80%. The results support the role of the T393C polymorphism as a predictive molecular marker for tumor response to cisplatin/5-FU-based radiochemotherapy in esophageal cancer.

The GNAS1 T393C polymorphism predicts survival in patients with advanced squamous cell carcinoma of the larynx

OBJECTIVES/HYPOTHESIS

In previous studies, we have demonstrated that the T-allele of a specific single nucleotide polymorphism (SNP) in the Galphas gene (T393C) correlates with increased Galphas expression and hence apoptosis. The T-allele was associated with a favorable outcome in a variety of human cancers, for example, carcinoma of the urinary bladder, kidney, colorectal, oro- and hypopharynx.

STUDY DESIGN

The prognostic value of the T393C SNP was retrospectively evaluated in an unselected series of patients treated with curative intent for laryngeal squamous cell carcinomas including all tumor stages with different therapeutic regimens.

METHODS

DNA analysis was performed using DNA from paraffin-embedded tissue samples from 157 patients (142 men, 15 women) with a median follow-up of 68 (3-143) months. The various genotypes were correlated with the overall survival.

RESULTS

Survival was significantly dependent on the T393C genotype in advanced American Joint Committee on Cancer (AJCC) stages (III-IV) with an apparent gene-dose effect (P = .0437). Five-year survival rates were 76% for TT, 49% for TC, and 43.5% for CC. In multivariate analysis including age at diagnosis, AJCC stage, grade, gender, and T393C genotypes, patients with CC genotype displayed a higher risk for death with a hazard ratio of 2.59 (95% confidence interval: 1.01-6.64, P = .047) compared with the reference group consisting of T393 homozygous individuals.

CONCLUSIONS

The T393C SNP is a prognostic marker that could help to identify high risk patients suffering from head and neck cancer.

Prognostic molecular markers in cholangiocarcinoma: a systematic review

The worldwide incidence of cholangiocarcinoma (CC) is steadily rising, with the incidence in United Kingdom (UK) now exceeding 1000 cases per year. It is an aggressive malignancy typified by unresponsiveness to the existing chemotherapy and radiotherapy regimes in the vast majority of cases. Surgery offers the only hope of a cure, though post-operative disease recurrence is common, with 5-year survival rates of less than 25% following resection. Developments in molecular techniques and improved understanding of the basis of carcinogenesis in CC has led to examination of the role of biomarkers in predicting poor outcome. This systematic review examines published evidence relating to the prognostic significance of these molecular markers in CC. Of the molecular markers which have been investigated to date, p53 mutation, cyclins, proliferation indices, mucins, CA19-9, CRP and aneuploidy appear to hold significant potential as predictors of outcome in CC. These and other biomarkers may themselves represent novel therapeutic targets for CC.

Genetics of biliary tract diseases: new insights into gallstone disease and biliary tract cancers

PURPOSE OF REVIEW

Chronic biliary diseases are due to complex interactions between environmental and genetic factors. Here we summarize the current knowledge of genetic factors that contribute to common biliary diseases, focusing on gallstones and carcinogenesis, and review the recent association studies.

RECENT FINDINGS

Since most studies were based on small sample sizes, replication of the findings is mandatory. Recently a large twin study confirmed a genetic predisposition to gallstones and a genome-wide association scan identified the hepatocanalicular cholesterol transporter ABCG8 as the common susceptibility factor for gallstone disease. Genetic studies in patients with cholangiocarcinoma indicate that genes controlling the metabolism and transport of xenobiotics or modulating chronic inflammation may determine individual susceptibility.

SUMMARY

Genetic studies have identified the first susceptibility factors for gallstones and biliary tract cancers, but most results have yet to be replicated. In the future, genome-wide studies in different populations are likely to identify the entire set of genes contributing to chronic biliary diseases. Since the disease phenotypes result from the manifestation of susceptibility factors under the influence of environmental triggers, the discovery of these genes will open avenues to control environmental challenges and lead to novel strategies for risk assessment ('gene signatures') and prevention.